1. Field of the Invention
The present invention generally relates to a radio frequency identification system (hereinafter, referred to as “RFID system”) including a memory for correcting a failed cell and a method for correcting a failed cell using the same, and more specifically, effectively correcting randomly distributed cell data by using a failed cell correcting circuit in a memory of a RFID system to improve a yield of the RFID system.
2. Description of the Related Art
Generally, a ferroelectric random access memory (hereinafter, referred to as “FeRAM”) has attracted considerable attention as the next generation memory device because it has a data processing speed as fast as a Dynamic Random Access Memory (hereinafter, referred to as ‘DRAM’) and preserves data even after the power is turned off.
The FeRAM having structures similar to the DRAM includes capacitors made of a ferroelectric substance, so that it utilizes the characteristic of a high residual polarization of the ferroelectric substance in which data is not deleted even after an electric field is eliminated.
The technical contents on the above FeRAM are disclosed in the Korean Patent Application No. 2001-57275 by the same inventor of the present invention. Therefore, the basic structure and the operation on the FeRAM are not described herein.
Meanwhile, the conventional FeRAM has a wide distribution map of cell data. In this case, cell data between “0” and “1” exists. As a result, when cell data is randomly distributed, it is difficult to repair a failed cell in a repair circuit and also to utilize cell data effectively.
Specifically, when a chip size is small like in a RFID system, it is difficult to test an embedded memory at the chip level. Accordingly, a test is performed at a RF tag level after high cost packaging is done. When a failed bit is found in a memory, the whole package is discarded and consequently causes high cost loss.